By Vera Eckert

ArcelorMittal on Thursday outlined plans and costs for steelmaking processes that produce less carbon, but also called for investment support from European Union states as well as carbon border taxes.

Europe's steelmakers like ArcelorMittal, are under pressure to cut carbon emissions while maintaining profitability in a market where there is fierce competition, mainly from China.

"The support the EU and member states can give to ensure we have a well-designed policy to make large-scale, competitive, carbon-neutral steelmaking a reality, is critical," Chief Financial Officer Aditya Mittal said on a call.

The company's green steelmaking plans were outlined in a climate action report on Thursday, which mapped out two processes to meet CO2 goals committed to last year. The aims were to cut its CO2 emissions by 30% by 2030 and to become carbon-neutral by 2050.

Mittal said the two processes were "smart carbon" and direct reduction of iron ore (DRI), both of which are being tested.

ArcelorMittal estimated the cost of deploying smart carbon at 15-25 billion euros (£13.5-23 billion) and 30-40 billion euros for DRI by 2050, not including infrastructure finance needs.

Mittal also called for an EU carbon border tax to fend off carbon-heavy steel imports. "We need a level playing field," he said.

ArcelorMittal's smart carbon process would use carbon recycled from bioenergy, green electricity, and carbon capture and storage within steelmaking.

This method could also use more scrap and would also benefit cement and plastics manufacturers, Mittal said.

The use of the DRI process to cut emissions involves a switch from natural gas to hydrogen as the fuel for steelmaking. But this hydrogen must come from purely green sources such as wind, sunshine or biomass, and it needs to become much cheaper.

Europe does not currently have enough green power capacity to devote to industries other than energy and needs to build up a hydrogen import infrastructure, stakeholders in the emerging hydrogen economy have said.

(Reporting by Vera Eckert, editing by Jane Merriman)